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Ultra-selective and fast transport of K+ are of significance for water desalination, energy conversion, and separation processes, but current bottleneck of achieving high-efficiency and exquisite transport is attributed to the competition from ions of similar dimensions and same valence through nanochannel communities. Here, inspired by biological KcsA channels, we report biomimetic charged porous subnanometer cages that enable ultra-selective K+ transport. For nanometer to subnanometer scales, conically structured double-helix columns exhibit typical asymmetric transport behaviors and conduct rapid K+ with a transport rate of 94.4 mmol m−2 h−1, resulting in the K+/Li+ and K+/Na+ selectivity ratios of 363 and 31, respectively. Experiments and simulations indicate that these results stem from the synergistic effects of cation-π and electrostatic interactions, which impose a higher energy barrier for Li+ and Na+ and lead to selective K+ transport. Our findings provide an effective methodology for creating in vitro biomimetic devices with high-performance K+ ion sieving. Materials for the selective transport of K+ have application in a variety of fields including water desalination and separation processes. Here the authors report charged porous subnanometer cages that are inspired in biological KcsA channels; high K+ transport rates and high K+/Li+ and K+/Na+ selectivity ratios are obtained, showing great potential in advanced sieving processes and efficient water treatments. [ABSTRACT FROM AUTHOR]

Biological ion channels, as fundamental units participating in various daily behaviors with incredible mass transportation and signal transmission, triggered booming researches on manufacturing their artificial prototypes. Biomimetic ion channel with the nanometer scale for smart responding functions has been successfully realized in sorts of materials by employing state-of-art nanotechnology. Ion track-etching technology, as crucial branches of fabricating solid-state nanochannels, exhibits outstanding advantages, such as easy fabrication, low cost, and high customization. To endow the nanochannel with smart responsibility, various modification methods are developed, including chemical grafting, non-covalent adsorption, and electrochemical deposition, enriching the reservoir of accessible stimuli-responses combinations, whereas were limited by their relatively lengthy and complex procedure. Here, based on the electric field induced self-assembly of polyelectrolytes, a universal customizable modifying strategy has been proposed, which exhibits superiorities in their functionalization with convenience and compatibility. By using this protocol, the channels' ionic transport behaviors could be easily tuned, and even the specific ionic or molecular responding could be realized with superior performance. This strategy surely accelerates the nanochannels functionalization into fast preparing, high efficiency, and large-scale application scenarios. [ABSTRACT FROM AUTHOR]

In pulverized coal particle combustion, part of the ash forms the ash film and exerts an inhibitory influence on combustion by impeding the diffusion of oxygen to the encapsulated char core, while part of the ash diffuses toward the char core. Despite the considerable ash effects on combustion, the fraction of ash film still remains unclear. However, the research of the properties of cenospheres can be an appropriate choice for the fraction determination, being aware that the formation of cenospheres is based on the model of coal particles with the visco-plastic ash film and a solid core. The fraction of ash film X is the ratio of the measuring mass of ash film and the total ash in coal particle. In this paper, the Huangling bituminous coal with different sizes was burnt in a drop-tube furnace at 1273, 1473, and 1673 K with air as oxidizer. A scanning electron microscope (SEM) and cross-section analysis have been used to study the geometry of the collected cenospheres and the effects of combustion parameters on the fraction of ash film. The results show that the ash film fraction increases with increasing temperature and carbon conversion ratio but decreases with larger sizes of coal particles. The high fraction of ash film provides a reasonable explanation for the extinction event at the late burnout stage. The varied values of ash film fractions under different conditions during the dynamic combustion process are necessary for further development of kinetic models. [ABSTRACT FROM AUTHOR]

Osmotic energy, existing between solutions with different concentrations, is a sustainable and ecofriendly resource for solving energy issues. However, current membrane-based osmotic energy conversion technologies focus on electricity generation from an “open” system by directly mixing salt (NaCl) solutions at room temperature. For the integrated utilization of thermal energy and higher power output performance, we demonstrate thermoenhanced osmotic energy conversion by employing highly soluble lithium bromide (LiBr) solutions, asymmetric sulfonated poly(ether ether ketone)/poly(ether sulfone) (SPEEK/PES) membranes, and LiMn2O4/carbon nanotube (LMO/CNT) electrodes. The thin top layer of this heat-resistant membrane contains hydrophilic groups (i.e., the sulfonated groups in SPEEK) that are beneficial for ion-selective transport. The thermal effect on each solution is investigated, and osmotic energy conversion can be improved by regulating the heat gradient. The power density is ~16.50 W/m2 by coupling with a temperature gradient (30 °C). This work is a step forward for promoting the performance of osmotic energy conversion with thermal energy assistance and provides the basis for a closed-loop system with regenerated osmotic energy from other energy forms. Moreover, the external field-osmotic hybrid energy conversion system shows powerful potential in the energy harvesting field.With the assistant of heat, the osmotic power generator with nanofluidic sulfonated poly(ether ether ketone)/poly(ether sulfone) membrane and high soluble lithium bromide shows excellent ion transport behavior and superior output power density for salinity gradient energy harvesting.Research Summary: For integrated utilization of sustainable energy and pursuing the high performance of the osmotic energy harvesting, the authors propose a strategy to couple the low-grade thermal energy with the salinity gradient energy by employing a thermoenhanced osmotic power generator. In the system, the LiBr with high solubility and the asymmetric sulfonated poly(ether ether ketone)/poly(ether sulfone) (SPEEK/PES) membranes with high stability and ion selectivity are both chosen for the thermo-enhanced osmotic energy harvesting. The proposed generator achieved the output power density of ~16.50 W/m2, extremely high value at 50-fold artificial sea water/river water condition, by coupling with the configuration of 30 ºC temperature gradient. Thus, by using the proposed system, the thermal energy, especially low-grade ones, has been well harvested and greatly improve the osmotic energy conversion. Thus, the external field-osmotic hybrid energy conversion system could show its great potentials in different fields with proper coupling. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is a cancer with high prevalence, and is one of the leading causes of cancer death worldwide. Metformin is a widely used hypoglycemic agent for type-2 diabetes mellitus (T2DM). Recently, metformin has drawn increasing attention in the field of cancer research for its emerging anti-cancer roles. However, the efficacy and underlying molecular mechanisms of metformin in the prevention and treatment for GC remain controversial. This review summarized the present clinical and mechanistic studies that investigated the efficacy of metformin in GC. It was found that the majority of clinical studies affirmed protective roles of metformin in both gastric cancer risk and survival rate. In addition, metformin's effects in the prevention and treatment for GC involve multiple pathways mainly via AMPK and IGF-1R. It was concluded that metformin presents a unique opportunity for application against GC, but further clinical and mechanistic investigations are required to solidify the roles of metformin in GC. [ABSTRACT FROM AUTHOR]

The emerging heterogeneous membranes show unprecedented superiority in harvesting the osmotic energy between ionic solutions of different salinity. However, the power densities are limited by the low interfacial transport efficiency caused by a mismatch of pore alignment and insufficient coupling between channels of different dimensions. Here we demonstrate the use of three-dimensional (3D) gel interface to achieve high-performance osmotic energy conversion through hybridizing polyelectrolyte hydrogel and aramid nanofiber membrane. The ionic diode effect of the heterogeneous membrane facilitates one-way ion diffusion, and the gel layer provides a charged 3D transport network, greatly enhancing the interfacial transport efficiency. When used for harvesting the osmotic energy from the mixing of sea and river water, the heterogeneous membrane outperforms the state-of-the-art membranes, to the best of our knowledge, with power densities of 5.06 W m−2. The diversity of the polyelectrolyte and gel makes our strategy a potentially universal approach for osmotic energy conversion. Heterogeneous membranes show great promise in harvesting the osmotic energy, but the performance is limited by the low interfacial transport efficiency. Here, the authors report use of a three-dimensional polyelectrolyte gel interface to achieve high-performance osmotic energy conversion. [ABSTRACT FROM AUTHOR]

The development of high‐efficiency electrocatalysts for large‐scale water splitting is critical but also challenging. In this study, a hierarchical CoMoSx chalcogel was synthesized on a nickel foam (NF) through an in situ metathesis reaction and demonstrated excellent activity and stability in the electrocatalytic hydrogen evolution reaction and oxygen evolution reaction in alkaline media. The high catalytic activity could be ascribed to the abundant active sites/defects in the amorphous framework and promotion of activity through cobalt doping. Furthermore, the superhydrophilicity and superaerophobicity of micro‐/nanostructured CoMoSx/NF promoted mass transfer by facilitating access of electrolytes and ensuring fast release of gas bubbles. By employing CoMoSx/NF as bifunctional electrocatalysts, the overall water splitting device delivered a current density of 500 mA cm−2 at a low voltage of 1.89 V and maintained its activity without decay for 100 h. [ABSTRACT FROM AUTHOR]